EP0913552B1 - Verfahren und Vorrichtung zum Erstellen eines zu einem existierenden Erdkabel parallelen Bohrlochs - Google Patents

Verfahren und Vorrichtung zum Erstellen eines zu einem existierenden Erdkabel parallelen Bohrlochs Download PDF

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Publication number
EP0913552B1
EP0913552B1 EP98308707A EP98308707A EP0913552B1 EP 0913552 B1 EP0913552 B1 EP 0913552B1 EP 98308707 A EP98308707 A EP 98308707A EP 98308707 A EP98308707 A EP 98308707A EP 0913552 B1 EP0913552 B1 EP 0913552B1
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EP
European Patent Office
Prior art keywords
strength
boring head
boring
locating signal
conveyance
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP98308707A
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English (en)
French (fr)
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EP0913552A3 (de
EP0913552A2 (de
Inventor
Hossein Eslambolchi
John Sinclair Huffman
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AT&T Corp
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AT&T Corp
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Filing date
Publication date
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Publication of EP0913552A3 publication Critical patent/EP0913552A3/de
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Publication of EP0913552B1 publication Critical patent/EP0913552B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B7/00—Special methods or apparatus for drilling
    • E21B7/04—Directional drilling
    • E21B7/046—Directional drilling horizontal drilling
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B44/00—Automatic control systems specially adapted for drilling operations, i.e. self-operating systems which function to carry out or modify a drilling operation without intervention of a human operator, e.g. computer-controlled drilling systems; Systems specially adapted for monitoring a plurality of drilling variables or conditions
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B47/00—Survey of boreholes or wells
    • E21B47/02—Determining slope or direction
    • E21B47/022—Determining slope or direction of the borehole, e.g. using geomagnetism
    • E21B47/0228—Determining slope or direction of the borehole, e.g. using geomagnetism using electromagnetic energy or detectors therefor

Definitions

  • This invention relates to a technique for accomplishing a cable boring operation substantially parallel to an existing underground utility conveyance.
  • Utilities such as those providing electric, gas, water and telephone service, often bury their conveyances (i.e., pipes and/or cables) underground for reasons of safety and aesthetics.
  • conveyances i.e., pipes and/or cables
  • the environment and terrain dictate the type of method employed for burying such conveyances.
  • utilities prefer direct burial which they accomplish by plowing or trenching the earth.
  • boring is preferred.
  • the utility, or a contractor under its employ first excavates a pit at each of the opposite ends of the intended route for the conveyance. From the one pit, a boring machine (auger) forces a boring head horizontally through the earth into the other pit to create a tunnel through which a utility conveyance can pass.
  • Underground utility conveyance burial by boring does create a certain risk.
  • An operator must carefully control the path of the boring head to avoid contact with one or more existing underground utility conveyances buried in proximity to the path created by the boring head.
  • many utilities such as AT&T, have regulations governing the minimum allowable distance permitted between the boring head and an existing underground utility conveyance.
  • a transmitter hereinafter referred to as a "sonde"
  • the signal transmitted by the sonde radiates through the ground for detection by one or more receivers located above ground.
  • the operator of the boring machine determines the relative position of the boring head as it bores a path through the earth to avoid contact with an existing underground utility conveyance.
  • the signal radiated by the sonde head tends to induce electromagnetic signals in other facilities, such as other underground utility conveyances, causing one or more of them to radiate signals in the vicinity of the conveyance of interest.
  • the receiver(s) tuned to receive the signal radiated by the sonde also receive the signals induced in, and radiated by, such other facilities, causing confusion regarding the actual position of the boring head. Since many boring operations occur in close proximity to existing underground utility conveyances, an error in determining the relative position of the boring head can prove disastrous. Indeed, boring operations have damaged existing underground conveyances, leading to service outages and lost revenues, not to mention the cost associated with repairs.
  • US-A-3 907 045 and US-A-3 853 185 disclose methods of boring a horizontal bore hole substantially parallel to an existing bore hole.
  • a signal generating apparatus such as an antenna is disposed in the existing bore hole and a suitable receiver is provided on the drill head. These methods do not however enable the drill head to detect an underground utility conveyance.
  • US-A-4 755 805 and US-A-5 027 108 disclose an electrically conducted boring device provided with means for detecting if the boring device electrically engages an underground high voltage source. This is to provide protection for the operator. However, there is no means for enabling the operator to steer the boring device so as to avoid contact with an underground high voltage source, and by the time contact with an underground high voltage utility conveyance is detected considerable damage is likely to have been done to the utility conveyance. Furthermore, this boring device is completely ineffective at detecting underground utility conveyances that are not high voltage sources (for example such as gas or water pipes).
  • high voltage sources for example such as gas or water pipes.
  • a first aspect of the present invention provides a method of providing an alert during a boring operation when a boring head is within a minimum allowable separation distance from an existing underground utility conveyance that radiates a locating signal of a pre-selected strength, the method comprising the steps of: detecting, at the existing utility conveyance, the strength of the locating signal; detecting the strength of the locating signal at the boring head; determining if the strength of the locating signal detected at the boring head exceeds a prescribed fraction of the strength of the locating signal detected at the existing utility conveyance; and if so generating an alert to indicate that the boring head is within the minimum allowable separation distance.
  • a second aspect of the invention provides an apparatus for providing an alert during a boring operation when a boring head is within a minimum allowable separation distance from an existing underground utility conveyance that radiates a locating signal of a pre-selected strength, the apparatus comprising: means for detecting, at the existing utility conveyance, the strength of the locating signal; means for detecting the strength of the locating signal at the boring head; means for determining if the strength of the locating signal detected at the boring head exceeds a prescribed fraction of the strength of the locating signal detected at the existing utility conveyance; and means for generating an alert to indicate that the boring head is within the minimum allowable separation distance.
  • the present invention provides a technique for generating an alert during a boring operation when the boring head is within a minimum allowable distance from an existing underground utility conveyance.
  • the method takes advantage of the fact that a typical existing underground utility conveyance radiates a locating signal that is unique to the service provider maintaining the conveyance.
  • the strength of the locating signal is monitored at the existing conveyance of interest, typically by means of an inductive clamp or the like for releasable attachment to the conveyance.
  • the strength of the locating signal radiated by the existing conveyance of interest is also monitored at the boring head, typically by way of a second inductive clamp.
  • the signal detected at the existing utility conveyance serves as a reference value with regard to the strength of the signal detected at the boring head. If the signal detected at the boring head exceeds a prescribed fraction of the strength of the signal detected at the existing conveyance, then the boring head is too close (i.e., within the minimum allowable distance from the existing conveyance) and an alert is generated.
  • the operation of the boring head may advantageously be controlled, in accordance with the strength of the locating signal, as detected at the boring head, in comparison to the strength of the locating signal detected at the conveyance.
  • FIGURE 1 shows an apparatus in accordance with the invention for both monitoring and controlling a boring head
  • FIGURE 1 depicts a boring operation conducted with the aid of a boring machine 10 known in the art.
  • a utility such as AT&T, or its contractor, excavates first and second bore pits 12 and 14 at opposite ends of an intended path for a utility conveyance (not shown). Thereafter, the utility or contractor places the boring machine 10, in the first pit 12.
  • An operator (not shown) operates the machine 10 to force a boring head 16 horizontally through that portion of the ground 18 between the boring pits 12 and 14. As boring machine 10 forces the boring head through the earth 18 from the first pit 12 into the second pit 14, the boring head creates a horizontal channel 20 for carrying a utility conveyance.
  • a boring operation of the type described occurs in the vicinity of an existing conveyance 22, such as a fiber-optic cable. Since the boring operation occurs "blind,” that is, without the ability to visually monitor the path of the boring head 16, the boring head may accidentally contact the fiber-optic cable 22, potentially damaging it.
  • monitoring of the path of the boring head 16 is accomplished with the aid of a sonde 23 within the boring head for radiating a signal in the range of 33 Hz. to 9 kHz.
  • One or more cable alert receivers 26 are placed above the earth 18 and monitor the signal radiated by sonde 23, thereby providing an indication of the relative position of the boring head 16.
  • the signal radiated by the sonde 23 induces a like signal in other facilities, such a metal sheath (not shown) surrounding the fiber-optic cable 22.
  • the metal sheath of the fiber-optic cable 22 radiates the induced signal to other facilities.
  • the receiver(s) 26 receive the signal radiated by such other facilities along with the signal radiated by the sonde 23.
  • the receiver(s) 26 may not accurately determine the relative position of the boring head 16. Not knowing the relative position of the boring head 16 can prove disastrous, especially when the boring operation occurs in close proximity to existing utility conveyances, such as the fiber-optic cable 22.
  • the present invention provides a technique for generating an alert when the boring head 16 becomes too close to (i.e., within a minimum allowable distance from) the existing fiber-optic cable 22.
  • the technique of the invention takes advantage of a locating signal that is radiated by the metal sheath of the fiber-optic cable 22.
  • the sheath of the fiber-optic cable 22 carries at least one locating signal for the purpose of locating the cable in the manner taught by U.S. patent 5,644,237, issued July 1, 1997, in the name of AT&T.
  • the cable locating signal and more particularly, its strength, serves as a point of reference for determining the relative position of the boring head 16 from the fiber-optic cable 22.
  • a differential signal monitor 28 receives on a first channel the signal radiated by the cable 22.
  • the signal monitor 28 receives the signal through an inductive clamp 30 adapted for releasable engagement about the cable.
  • inductive clamps are well known, and are exemplified by the type associated with current measurement devices.
  • a second inductive clamp 32 couples the locating signal induced in the boring head 16 from the fiber-optic cable 22 to the signal monitor 28.
  • the signal monitor 28 compares the strength of the signal induced in the boring head 16, as detected via the clamp 32, relative to the strength of the locating signal at the fiber-optic cable 22, as detected via the clamp 30.
  • the signal monitor utilizes the strength of the locating signal at the fiber-optic cable 22 as a reference value against which the strength of the signal received at the boring head 16 is compared.
  • the strength of the locating signal induced in the boring head 16 generally varies inversely with the distance of the boring head from the fiber-optic cable 22. Thus, the closer the boring head 16 is to the fiber-optic cable 22, the greater the strength of the locating signal induced in the boring head. Conversely, the farther the boring head 16 is from the fiber-optic cable 22, the weaker the signal induced in the boring head.
  • the strength of the locating signal on the fiber-optic cable 22 itself influences the strength of the signal induced in the boring head 16. Hence, it is necessary to take account of the strength of the locating signal when examining the strength of the locating signal induced in the boring head 16.
  • the signal monitor stores a reference value representing the ratio of the strength of the signal induced in the boring head 16 to the strength of the locating signal at the fiber-optic cable 22 obtained when the boring head 16 is no closer to the fiber-optic cable 22 than the minimum allowable distance. Should the ratio of the strength of the locating signal detected at the boring head 16 to the strength of the locating signal at the fiber-optic cable 22 exceed the reference value, then the signal monitor 28 knows that the boring head is too close to the cable. Under such conditions, the signal monitor 28 actuates an alarm 31 that generates an alert, either in the form of a visual and/or audible warning, to apprise the operator of the boring machine 10 of the close proximity of the boring head 16 to the fiber-optic cable 22. Upon generation of the warning by the alarm 31, the operator of the boring machine 10 presumably takes appropriate action to avoid damaging the fiber-optic cable 22.
  • the signal monitor may also generate a control signal (represented by the dashed line in FIG. 1) to control the boring machine 10.
  • the signal monitor 28 generates the control signal in accordance with the ratio of the strength of the locating signal detected at boring head 16 to the strength of the locating signal detected at the fiber-optic cable 22.
  • the boring machine 10 controls the operation of the boring head 16 to maintain the boring head 16 substantially parallel to the fiber-optic cable 22 at a prescribed separation distance therefrom in accordance with the control signal. If the control signal increases beyond a quiescent level that corresponds to the prescribed separation distance of the boring head 16 from the fiber-optic cable 22, the boring machine 10 displaces the boring head away from the cable.
  • the signal monitor 28 reduces the strength of the control signal, causing the boring machine 10 to displace the boring head closer to the fiber-optic cable 22.
  • the control signal magnitude increases, causing the boring machine to displace the boring head away from the cable.
  • the boring machine 10 controls the displacement of the boring head 16 so that the boring head bores substantially parallel to the fiber-optic cable 22.
  • the foregoing describes a technique for providing an alert when the boring head is within a minimum allowable distance from an existing underground utility conveyance, as well as for controlling the operation of the boring head to bore substantially parallel to the existing conveyance.

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  • Engineering & Computer Science (AREA)
  • Geology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Mechanical Engineering (AREA)
  • Electromagnetism (AREA)
  • Geophysics (AREA)
  • Geophysics And Detection Of Objects (AREA)
  • Earth Drilling (AREA)

Claims (8)

  1. Verfahren zum Bereitstellen eines Alarms während eines Bohrvorgangs, wenn ein Bohrkopf (16) innerhalb eines minimalen zulässigen Trennabstands von einer existierenden Untergrundeinrichtungs-Beförderungseinheit (22) ist, die ein Lokalisierungssignal mit einer vorgewählten Stärke abstrahlt, wobei das Verfahren die folgenden Schritte umfasst:
    a. Erfassen, an der existierenden Einrichtungs-Beförderungseinheit (22), der Stärke des Lokalisierungssignals;
    b. Erfassen der Stärke des Lokalisierungssignals an dem Bohrkopf (16);
    c. Bestimmen, wenn die Stärke des Lokalisierungssignals, das an dem Bohrkopf (16) erfasst wird, einen vorgegebenen Teil der Stärke des Lokalisierungssignals, das an der existierenden Einrichtungs-Beförderungseinheit (22) erfasst wird, übersteigt; und wenn dem so ist, gekennzeichnet durch
    d. Erzeugen eines Alarms, um anzuzeigen, dass der Bohrkopf (16) innerhalb des minimalen zulässigen Trennabstands von der Einrichtungs-Beförderungseinheit (22) ist.
  2. Verfahren nach Anspruch 1, wobei der Alarm ein visueller Alarm ist.
  3. Verfahren nach Anspruch 1, wobei der Alarm ein hörbarer Alarm ist.
  4. Verfahren nach Anspruch 1, wobei der Alarm die Kombination eines hörbaren Alarms und eines visuellen Alarms umfasst.
  5. Verfahren nach Anspruch 1, femer umfassend den folgenden Schritt:
    e. Steuern des Bohrkopfs (16) während des Bohrvorgangs in Übereinstimmung mit dem Verhältnis der Stärke des Lokalisierungssignals, das an dem Bohrkopf erfasst wird, zu der Stärke des Lokalisierungssignals, das an der existierenden Einrichtungs-Beförderungseinheit (22) erfasst wird.
  6. Verfahren nach irgendeinem vorangehenden Anspruch und femer umfassend die folgenden Schritte:
    Erzeugen eines Steuersignals in Übereinstimmung mit dem Verhältnis der Stärke des Lokalisierungssignals, das an dem Bohrkopf (16) erfasst wird, zu der Stärke des Lokalisierungssignals, das an der existierenden Einrichtungs-Beförderungseinheit (22) erfasst wird, und
    Versetzen des Bohrkopfs (16) während des Bohrvorgangs relativ zu der existierenden Einrichtungs-Beförderungseinheit (22) in Übereinstimmung mit dem Steuersignal derart, dass das Steuersignal im wesentlichen konstant bleibt, wobei der Bohrkopf (16) im wesentlichen parallel zu der existierenden Einrichtungs-Beförderungseinheit (22) gehalten wird.
  7. Vorrichtung zum Bereitstellen eines Alarms während eines Bohrvorgangs, wenn ein Bohrkopf (16) innerhalb eines minimalen zulässigen Trennabstands von einer existierenden Untergrundeinrichtungs-Beförderungseinheit (22) ist, die ein Lokalisierungssignal einer vorgewählten Stärke abstrahlt, wobei die Vorrichtung umfasst:
    a. eine Einrichtung (30) zum Erfassen, an der existierenden Einrichtungs-Beförderungseinheit, der Stärke des Lokalisierungssignals;
    b. eine Einrichtung (32) zum Erfassen der Stärke des Lokalisierungssignals an dem Bohrkopf;
    c. eine Einrichtung (28) zum Bestimmen, wenn die Stärke des Lokalisierungssignals, das an dem Bohrkopf erfasst wird, einen vorgeschriebenen Teil der Stärke des Lokalisierungssignals, das an der existierenden Einrichtungs-Beförderungseinheit erfasst wird, übersteigt; und dadurch gekennzeichnet, dass sie femer umfasst:
    d. eine Einrichtung (28, 31) zum Erzeugen eines Alarms, um anzuzeigen, dass der Bohrkopf (16) innerhalb des minimal zulässigen Trennabstands von der Einrichtungs-Beförderungseinheit (22) ist.
  8. Vorrichtung nach Anspruch 7 und ferner umfassend:
    e. eine Einrichtung (28) zum Erzeugen eines Steuersignals in Übereinstimmung mit einem Verhältnis der Stärke des Lokalisierungssignals, das an dem Bohrkopf (16) erfasst wird, zu der Stärke des Lokalisierungssignals, das an der existierenden Einrichtungs-Beförderungseinheit (22) erfasst wird; und
    f. eine Einrichtung (10), die auf das Steuersignal anspricht, zum Versetzen des Bohrkopfs (16) während des Bohrvorgangs relativ zu der existierenden Einrichtungs-Beförderungseinheit (22) in Übereinstimmung mit dem Steuersignal derart, dass das Steuersignal im wesentlichen konstant bleibt, wobei der Bohrkopf (16) im wesentlichen parallel zu der existierenden Einrichtungs-Beförderungseinheit (22) gehalten wird.
EP98308707A 1997-10-29 1998-10-23 Verfahren und Vorrichtung zum Erstellen eines zu einem existierenden Erdkabel parallelen Bohrlochs Expired - Lifetime EP0913552B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US08/959,873 US5929758A (en) 1997-10-29 1997-10-29 Method and apparatus for achieving parallel cable boring
US959873 1997-10-29

Publications (3)

Publication Number Publication Date
EP0913552A2 EP0913552A2 (de) 1999-05-06
EP0913552A3 EP0913552A3 (de) 2000-05-17
EP0913552B1 true EP0913552B1 (de) 2004-07-21

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EP98308707A Expired - Lifetime EP0913552B1 (de) 1997-10-29 1998-10-23 Verfahren und Vorrichtung zum Erstellen eines zu einem existierenden Erdkabel parallelen Bohrlochs

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US (1) US5929758A (de)
EP (1) EP0913552B1 (de)
CA (1) CA2250666A1 (de)
DE (1) DE69825117T2 (de)

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US6411094B1 (en) * 1997-12-30 2002-06-25 The Charles Machine Works, Inc. System and method for determining orientation to an underground object
IE990565A1 (en) * 1999-07-07 2001-02-21 Dermot Gerard O'dwyer A device for detecting the proximity of an underground cable during digging
US20060293368A1 (en) * 2005-01-13 2006-12-28 Zhang Geoff G Amorphous N-(2-((4-hydroxyphenyl)amino)pyridin-3-yl)-4-methoxybenzenesulfonamide hydrochloride
US20070021470A1 (en) * 2005-01-13 2007-01-25 Jorge Gandarilla Crystalline N-(2-((4-Hydroxyphenyl)amino)pyridin-3-yl)-4-methoxybenzenesulfonamide methanolates
US20070004781A1 (en) * 2005-01-13 2007-01-04 Schmitt Eric A Crystalline N-(2-((4-hydroxyphenyl)amino)pyridin-3-yl)-4-methoxybenzenesulfonamide hydrochloride
US20060293367A1 (en) * 2005-01-13 2006-12-28 Zhang Geoff G Amorphous N-(2-((4-hydroxyphenyl)amino)pyridin-3-yl)-4-methoxybenzenesulfonamide
US20070021471A1 (en) * 2005-01-13 2007-01-25 Jorge Gandarilla Crystalline N-(2-((4-Hydroxyphenyl)amino)pyridin-3-yl)-4-methoxybenzenesulfonamide ethanolates
EP1836170A1 (de) * 2005-01-13 2007-09-26 Abbott Laboratories N-(2z)-2-(4-hydroxyphenyl)imino)-1,2-dihydro-3-pyridinyl)-4-methoxybenesulfonamid kristallform 2
WO2007038940A1 (en) * 2005-09-20 2007-04-12 Telecom Italia S.P.A. A boring head, a method and an apparatus for accomplishing a conveyance line boring operation

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Also Published As

Publication number Publication date
CA2250666A1 (en) 1999-04-29
US5929758A (en) 1999-07-27
EP0913552A3 (de) 2000-05-17
DE69825117D1 (de) 2004-08-26
DE69825117T2 (de) 2005-08-18
EP0913552A2 (de) 1999-05-06

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